In the fabrication of integrated circuits (ICs), it is oftentimes desirable to deposit a thin film of material which substantially conforms to the shape of features already present on the surface of a partially manufactured semiconductor wafer. While there are various ways of depositing films of material on a semiconductor such as physical vapor deposition (PVD), chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), etc., these methodologies often result in the formation of layers not sufficiently conformal with the underlying material. Atomic layer deposition (ALD), on the other hand, does typically provide for the deposition of thin films with the desired degree of conformality.
ALD achieves its characteristic conformality by depositing material in thin adsorption-limited layers. Since each deposited layer is formed through an adsorption-limited process, each layer is of approximately the same thickness, and thicker films of the deposited material consisting of multiple layers may be thus formed through consecutive ALD cycles, thereby producing a film which conforms to the shape of the underlying substrate surface.